For the 3rd generation mobile communications systems, such as UMTS (Universal Mobile Telecommunications Systems), data transfer architectures have been introduced between a core network (CN) and UTRAN (UMTS Terrestrial Radio Access Net-work), and also between UTRAN and UE (User Equipment). The architecture of the UMTS is known for the person skilled in the art, and therefore, it will be not disclosed herein in details. The possible UMTS architectures have been introduced e.g., by 3rd Generation Partnership Project (3GPP) in a technical specification 3G TS 23.002 (Network Architecture), which is incorporated herein by reference.
The data transfer architectures are divided into two main categories, i.e., a non-access stratum and an access stratum. The non-access stratum offers higher layer (e.g., a network layer) signaling, such as Mobility Management (MM) and Call Control (CC), between network elements. The access stratum is the functional grouping consisting of the parts in the infrastructure and in the user equipment and the protocols between these parts being specific to the access technique. The access stratum provides services related to the transmission of data over the radio interface and the management of the radio interface to the other parts of UMTS. The access stratum offers services for the non-access stratum through the Service Access Point (SAPs), such as General Control (GC) SAPs, Notification (Nt) SAPs and Dedicated (DC) SAPs. The service can be defined by a set of service primitives, or operations, that a lower layer provides to upper layer or layers. The services provided by and for a user equipment are classified for five categories: tele-services (e.g., speech, emergency call, short message service, cell broadcast service), bearer services (information transfer attributes and information quality attributes), supplementary services (e.g., call forwarding, Advice of Charge, explicit call transfer), service capabilities (e.g., mobile station execution environment, location services, SIM Application Toolkit), and GSM system features (e.g., Network Identity and Time Zone, Unstructured Supplementary Service Data).
A physical layer of UTRAN (being a part of an access stratum), i.e., layer 1 in OSI Reference Model (which is well known to a person skilled in the art), is based on WCDMA (Wideband Code Division Multiple Access). The physical layer interfaces a Medium Access Control (MAC)-layer, which is a sub-layer of layer 2 (i.e., data link layer), and offers different transport channels to MAC. The transport channel is characterized by how (not what kind of data) the information is transferred over a Radio Interface. The characteristics of a transport channel are defined by its transport format, specifying the physical layer processing to be applied to the transport channel in question, such as convolutional channel coding and interleaving, and any service specific rate matching as needed. There are two duplex modes (e.g., for UTRA (UMTS Terrestrial Radio Access)), i.e., FDD (Frequency Division Duplex) and TDD (Time Division Duplex).
FDD is a duplex method whereby uplink and downlink transmissions use two separated radio frequencies. In FDD, each uplink and downlink uses the different frequency band. The present invention relates to the FDD mode for transmission of data.
TDD is a duplex method whereby uplink and downlink transmissions are carried over the same radio frequency by using synchronized time intervals. In the TDD, time slots in a physical channel are divided into transmission and reception part, and information on uplink and downlink are transmitted reciprocally.
The physical layer operates exactly according to the layer 1 radio frame timing. A transport block is defined as the data accepted by the physical layer to be jointly encoded. A transport block is a basic unit exchanged between layer 1 and MAC, for layer 1 processing, and a transport block size is the number of bits in a transport block. The transport block size is always fixed within a given transport block set (which is a set of transport blocks), i.e., all transport blocks within a transport block set are equally sized.
A UE can set up multiple transport channels simultaneously, each one of them having its own characteristics, and each transport channel can be used for information stream transfer of one radio bearer from or for layer 2 (i.e., data link layer) and higher layer signaling messages.
The transport channels (uplink and downlink channels) can be divided into two main categories dedicated transport channels (e.g., a dedicated channel, DCH) and common transport channels (e.g., Random Access Channel, RACH). The dedicated transport channels are dedicated to one UE, and therefore, the inband identification of UE is not needed. Common transport channels are shared by several users, and inband identification of UE is needed. The identification of a UE is achieved by a Radio Network Temporary Identity (RNTI) field of MAC-layer. The multiplexing of the transport channels onto the same or different physical channels is carried out by layer 1.
The channel coding and multiplexing generally comprise the following steps (not necessarily in this order):                CRC (Cyclic Redundancy Code) attachment is added to a transport block.        Inserting a tail bit attachment to the ‘transport block+CRC’.        Convolutional coding (or alternatively turbo coding or alternatively no coding) of ‘transport block+CRC+tail bit attachment’.        Rate matching.        1st interleaving.        Radio frame segmentation.        (Possible) 2nd interleaving.        Transmitting radio frames through the physical channel to the receiving party (i.e., UE or Access Network or Core Network).        
The present day decoding and demultiplexing methods are based on the technical specifications of 3GPP. The following steps apply to common channel processing. After receiving the radio frame in a receiver (e.g., a RAKE-receiver of a UE), the radio frame is processed by the UE. The processing includes deinterleaving, rate matching, turbo decoding (or alternatively convolutional decoding or alternatively no decoding), calculating a CRC checksum. Then the result of the previous processes will be transferred to the MAC, which identifies (if needed) the UE by identifying a Radio Network Temporary Identity (RNTI) transmitted in a radio frame. In other words, a UE decodes all packets on all transport channels multiplexed on one physical channel up to a MAC level, where the UE, based on the RNTI, determines whether the message is destined for it, or whether it is destined to another UE and should be discarded. Thereafter, the MAC layer transfers the received data for higher layers.
The above method may, however, prove inefficient as the bandwidth of the physical channel may be considerably higher than the service the UE has ordered. Furthermore, the UE needs to carry out several processes before identifying whether the radio frame is destined to the UE or to some other UE(s). Carrying out several processes consumes valuable power (e.g., battery) of the UE.